Move UDSPControl structure into DSP.h .
Move mixer construction to AudioCommon.cpp.
Delete AudioCommon::UseJIT().
Move audio handling out of DSP emulation.

This is good for a couple of reasons: one, it gets rid of duplicated code,
and two, DSP emulation shouldn't need to interact with audio in the first
place.
Don't cast -1 to enum to represent a missing value.

This is undefined behavior in C++, and a clang warning suggests it is
actually producing bad code as a result:

../Source/Core/VideoCommon/BPFunctions.cpp:164:45: warning: comparison of constant 4294967295 with expression of type 'PEControl::PixelFormat' is always false [-Wtautological-constant-out-of-range-compare]
        if (new_format == old_format || old_format == (unsigned int)-1)
Fix harmless warnings.
Merge pull request #222 from comex/more-clang-fixes

More clang fixes
Merge pull request #220 from magumagu/audio-handling-cleanup-v2

Audio handling cleanup v2
ogl: fix signed vs unsigned comparison warning
ShaderGen/D3D: inline centroid
ShaderGen: merge early-z blocks of ogl+d3d
ShaderGen: use cbuffers for D3D
ShaderGen: inline constant shaders
PixelShaderGen: change the way to handle which constant is used
ShaderGen: drop manual register positions
PixelShaderGen: drop fmod as it isn't used any more
PixelShaderGen: extract iround
ShaderGen: make clipPos readonly
ShaderGen: OGL: don't make a copy of "Normal"
ShaderGen: make uv readonly